Parser configuration strip-aliased does not work with coerce

Even when parser configuration `strip-aliased` is `true`, then it does not work if an option has `coerce`, e.g. see:
```js
const args = require("yargs")
    .parserConfiguration({ "strip-aliased": true })
    .option("log", { alias: ["l", "ll"], coerce: s => s })
    .parse("-l 1");
delete args["$0"]; delete args["_"];
// args is { log: 1, l: 1, ll: 1 } 
```